Probing Baryons in the Universe

Adapted from Todd M. Tripp, UMass Amherst and NASA Galaxy Evolution Explorer

Probing Baryons in the Universe

Sèvres, France. 14-18 Nov. 2016

Baryons account for 17% of the gravitating mass of the Universe and are found in different components, stars (6%), cold gas (2%) and ionized, diffuse halo gas (90%) according to their last inventory (Fukugita & Peebles, 2004) as well as recent studies of the HST.


The most important techniques to probe the baryonic matter is through the absorption lines present along the lines of sight of bright background sources, such as quasars or gamma-ray bursts.

In this way baryons can be probed on all scales: from high density structures, such as the inner part of galaxies, to the haloes and then to the filaments of the inter-galactic medium. An important related question is that of the missing baryons, since their inventory at z=2 seems to exceed by a factor 2 that in the nearby Universe. The discovery of circumgalactic hot and warm-hot gas in nearby galaxies may have a considerable impact in cosmology since these are the most important source of baryons.

In this workshop we will discuss about the following topics related to the exploration of the baryonic matter from the earliest epochs to the local universe:

  • probing galaxies at high redshift: QSO and GRB lines of sight - the nature of high redshift GRBs and their progenitors
  • the IGM probed by QSOs
  • galactic and intergalactic baryons in the local universe
  • where are the missing baryons?
  • baryons probed with X-rays
  • hot and cool gas surrounding nearby galaxies
  • future instrumentation (SVOM, Athena, ELT, SKA,...)

Invited speakers (confirmed):

  • Bertrand Cordier
  • Frédéric Daigne
  • Michel Dennefeld
  • Valentina D'Odorico
  • Taotao Fang
  • Andrew J. Fox
  • Johan Fynbo
  • Francois Hammer
  • Joseph Hennawi
  • Di Li
  • Xiaowei Liu
  • Fabrizio Nicastro
  • Pasquier Noterdaeme
  • Céline Péroux
  • Patrick Petitjean
  • Bo Qin
  • Philipp Richter
  • Daniel Schaerer
  • Benoit Semelin
  • Mike Shull
  • Jianyan Wei
  • Xuebing Wu
  • Qingjuan Yu
  • Shuangnan Zhang